It's new TNGA platform will also allow for 20 percent less vehicle weight

Toyota Motor Corp. is shedding more light on the upcoming fourth-generation Toyota Prius, including a whole new design and at least an 8 percent gain in fuel economy.

According to Automotive News, Toyota is looking to make some major changes in design, manufacturing and technology for the next Prius, which is due to be released in a year.

For starters, the next-gen Prius will be the first (or one of the first) Toyota vehicles based on the automaker's latest platform, "Toyota New Global Architecture" (TNGA). TNGA aims to improved engineering and low-cost as well as flexible manufacturing.

This platform will call for a major redesign of the Prius' looks. TNGA means lower-slung vehicles with a more planted stance and lower center of gravity, which should improve handling and offer a sportier look.

One possible design direction for the next generation Prius -- the FT-Bh concept

Chris Hostetter, Toyota's vice president for strategic planning in the U.S., has said that the Prius could use a new look.

"There's an undercurrent among most people that they're ready for a new Prius look," said Hostetter. "Maybe our architecture has been a little bit similar for the last two generations."

The Prius, which was first launched in Japan in 1997 and the U.S. in 2000, had an exterior design that was altered from Toyota's Yaris sedan. The second-generation Prius was released in 2003, and it received the raked hood and windshield. From 2003 to 2004, Prius sales increased dramatically from 43,162 to 125,742. Toyota is likely hoping to do the same with a completely redesigned fourth-generation Prius.

Aside from design, the new Prius is getting a makeover under the hood. Its new ultra-efficient gasoline engine will achieve thermal efficiency rates above 40 percent, which is a nice boost from 38.5 percent in the current Prius.

Toyota also talked batteries in its latest Prius revelations. It’s deciding whether to use lithium ion batteries for its fourth-generation Prius, or to offer some models with lithium ion and others with nickel-metal hydride batteries. While Toyota likes the power and energy performance of lithium ion, it worries about the cost compared to nickel-metal hydride batteries.

Satoshi Ogiso, managing officer in charge of global product planning at Toyota, said the automaker is pushing for at least an 8 percent improvement in fuel economy, which is slightly less than the 10 percent gains each Prius before it has received.

"Generally speaking, hybrid powertrains are more mature than before. So, the general tendency is that when a technology matures, the improvement ratio is saturating, dropping," said Ogiso. "We will do our best effort to keep that pace."

But the fact that TNGA models will cut vehicle weight will be helpful. It was reported that Toyota should be able to cut overall vehicle weight by up to 20 percent on TNGA models, which includes the new Prius.

Toyota mentioned lighter components, such as its new one-size-fits-all heating and air-conditioning unit that 20 percent smaller than the previous Prius generation's.

Jonny Lieberman, senior features editor at Motor Trend, recently spoke with his sources at Toyota and shared a bit of secret info about the next Prius. Lieberman hinted that the next Prius would have a fuel economy rating of 60 mpg. This shouldn't be too hard to achieve assuming a lighter vehicle weight, more powerful electric motor, and a possible switch from NiMH to lithium-ion batteries.